In recent years, many computer apparatuses have been used while being connected to a network such as the Internet, a company network or a LAN (Local Area Network). The network includes a server connected as a computer apparatus for offering services, and various information is stored in the server. By connecting a computer apparatus as a terminal to the server via the network, a user can obtain various information therefrom.
For a user to acquire information, processing is required to extract target information from a large amount of stored information. In one method, for example, a user designates a keyword that may be included in target information. Data including that keyword is extracted from a large amount of stored information. In such extraction processing, a program called a retrieval engine has been widely used. The retrieval engine widely searches through information stored in a server and automatically extracts data that includes a keyword designated by a user.
However, it is not necessarily true that all the data obtained using such a retrieval engine are target information a user wishes to find. For example, a user wishes to obtain information about “OLE for Process Control”, often represented by an abbreviation “OPC”. If a retrieval is carried out using the full expression “OLE for Process Control” as a keyword, information expressed as “OPC” can not be acquired. In view of this limitation, using a retrieval implemented by including “OPC” as a keyword in an “OR” connection, will enable all the data including “OPC” to be extracted.
However, “OPC” is also an abbreviation of “Organic Photo Conductor”. Consequently, the retrieval engine extracts not only those data about “OLE for Process Control” the user wishes to find, but also those data about “Organic Photo Conductor” that are totally irrelevant. Therefore, the user has to select desired data individually from the extracted data. In this event, as the amount of the extracted data increases, searching for target data requires more time and more labor.
To exclude the totally irrelevant data about “Organic Photo Conductor”, a new keyword relating to “OLE for Process Control”, such as “control”, can be added in an “AND” connection with “OPC”, thereby focusing the extracted data on the desired topic. However, if this processing is carried out, those data about “OLE for Process Control” including “OPC” but not including the word “control” can not be extracted. Consequently, even those data actually relating to “OLE for Process Control” which should be extracted are excluded. Accordingly, there arises a problem that when retrieval is configured to exclude unnecessary data as described above, necessary data may also be excluded, thus failing to obtain target data.
What is needed is a retrieval system that can more accurately extract the information required by the user. The need for such a system has heretofore remained unsatisfied.